Process for making fibrous insulating products



Patented Sept. 6, 1932 UNITED STATES A ENT;Q FEEFFI FRIEDRICH GRUNDER, F MUNCI-IENSTEIN, NEAR BASEL, SWITZERLAND PROCESS FOR MAKING FIBROUS INSULATIhl'G PRODUCTS No Drawing.v Application filed. November f), 1929, Serial No. 406,168, and in Switzerland December 4, 1928.

This invention relates to a process for making fibrous insulating products from vegetable fibres.

One important object of the invention is to produce an insulating product from vegetable fibres wherein the fibres are adhesively bound together by colloidal adhesion, the colloidal adhesive substance being produced from the fibres themselves. a Y r A second important object of the invention is to provide an improved process wherein the product has its fibres bound together without the use of heavy pressure so that the product is highly aeriterous and thus forms an insu- 35 lator against heat and sound.

A third important object of the invention is to provide an improved process for manufacturing such a product wherein the material is conveyed to forming molds by compressed air so as to be thoroughly aerated when filled into the molds.

With the above and other objects in view,

one method of carrying the process into exe-, cution will now be specifically described.

I To 70% of wood waste, such'as saw dust, shavings and the like, is mixed with of vegetable fibre such as is derived from reeds, hemp, flax, jute, roots, sea-grass, kapok and the like. Thismixture is then softened in a 30 bath of caustic soda and macerated until the fibres acquire a felt-like condition, part of the fibres being reduced to a colloidal condition at the same time. The excess solution or bath is then removed and the pasty composition remaining is pulverized in a mill. In

this pulverized state, the material is then conveyed to any suitable molds by compressed air. In this molded state there will still be considerable free moisture in the composition which is at least partly expelled by lightly pressing the molded articles as by running the articles on a belt between pressing rollers. The product is now dried and is ready for use.

Another method of carrying out the process is to treat the wood waste to be used sepa-' rately and this separated wood waste is used for the production of colloidal adhesive by softening in a solution of NaOH of 410 Baum. The remaining fibres are treated from 5 to 10 hours in a caustic solution of 5}) KOH of 1015 Baum mixed with H SO of Baum. The excess of the respective baths is removed and the residues are treated with HCl to neutralize the alkali. Both residues are now subjected to a cleansing operation and of the treated wood waste is mixed with 30% of the other fibres. Themixture is new ground to a fibre length of 1 to 3 millimeters and molded, pressed and dried as in the first method. 0

I claim: 1. That process of producing heat and sound insulating articles which consists of taking a mass of wood waste and other vegetable fibres both of which have been treated,6 in an alkaline bath and have had excess bath removed, comminuting the mass, conveying the co-mminuted mass to a mold by a compressed air currentwhereby the mass as aerated, lightly pressing the molded mass to ex- 3' 'pel at least a portion of the moisture, and

drying the lightly pressed mass.

2. That process of producing ,heat and sound insulating articles which consists in mixing 7 0% vegetable fibres, treating the mass in a bath of caustic alkali untilat least'a portion of the wood waste assumes a colloidal condition, separating the excess bath from the mass, comminuting the mass, conveying the comminuted mass to a mold by a current 01 compressed air to aerate the mass, pressing the molded material lightly to an extent sufli cient only to remove a part at least of any residue from the bath without forcing out; the air from the mass, and drying the pressed material.

3. That process of producing sound and heat insulating articles which consists in treating wood waste with a solution of so-;

or" wood waste with 30% of otherdium hydroxide of 4 to 10 Baum, treating other vegetable fibres with a mixture of a potassium hydroxide solution of a strength of l015 Baum and sulphuric acid of a strength of 50 Baum for five to ten hours, removing the excess bath from each mass, mixing 70% of the treated Wood Waste With 30% of the treated other fibres, comminuting the mixed mass, conveying the comminuted mass to a mold by a current of compressed air to aerate the mass, lightly pressing the molded mass, and drying the pressed mass.

In testimony whereof I affix my signature. 7

FRIEDRICH GRUNDER, Orv. ING. 

